document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=993318>Question 993318</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A student buys some pens for 400$. If the cost of each pens is 9$ less, he can buy 9 pens more from the same money. Find the number of pens  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #612586 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=612586\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n+ ALIGN=MIDDLE  ALT=\"+n+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the number of pens<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+400%2Fn+-+9+=+400%2F%28+n%2B9+%29+ ALIGN=MIDDLE  ALT=\"+400%2Fn+-+9+=+400%2F%28+n%2B9+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiply both sides by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n%2A%28+n%2B9+%29+ ALIGN=MIDDLE  ALT=\"+n%2A%28+n%2B9+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+400%2A%28+n%2B9+%29+-+9%2An%2A%28+n%2B9+%29+=+400n+ ALIGN=MIDDLE  ALT=\"+400%2A%28+n%2B9+%29+-+9%2An%2A%28+n%2B9+%29+=+400n+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+400n+%2B+3600+-+9n%5E2+-+81n+=+400n+ ALIGN=MIDDLE  ALT=\"+400n+%2B+3600+-+9n%5E2+-+81n+=+400n+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+9n%5E2+%2B+81n+-+3600+=+0+ ALIGN=MIDDLE  ALT=\"+9n%5E2+%2B+81n+-+3600+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n%5E2+%2B+9n+-+400+=+0+ ALIGN=MIDDLE  ALT=\"+n%5E2+%2B+9n+-+400+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Use quadratic formula<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n+=+%28+-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29+%2F+%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"+n+=+%28+-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29+%2F+%282%2Aa%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+=+1+ ALIGN=MIDDLE  ALT=\"+a+=+1+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+9+ ALIGN=MIDDLE  ALT=\"+b+=+9+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+-400+ ALIGN=MIDDLE  ALT=\"+c+=+-400+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n+=+%28+-9+%2B-+sqrt%28+9%5E2-4%2A1%2A%28-400%29+%29%29+%2F+%282%2A1%29+ ALIGN=MIDDLE  ALT=\"+n+=+%28+-9+%2B-+sqrt%28+9%5E2-4%2A1%2A%28-400%29+%29%29+%2F+%282%2A1%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n+=+%28+-9+%2B-+sqrt%28+81+%2B+1600+%29%29+%2F+2+ ALIGN=MIDDLE  ALT=\"+n+=+%28+-9+%2B-+sqrt%28+81+%2B+1600+%29%29+%2F+2+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n+=+%28+-9+%2B-+sqrt%28+1681+%29%29+%2F+2+ ALIGN=MIDDLE  ALT=\"+n+=+%28+-9+%2B-+sqrt%28+1681+%29%29+%2F+2+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n+=+%28+-9+%2B+41+%29+%2F+2+ ALIGN=MIDDLE  ALT=\"+n+=+%28+-9+%2B+41+%29+%2F+2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n+=+32%2F2+ ALIGN=MIDDLE  ALT=\"+n+=+32%2F2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n+=+16+ ALIGN=MIDDLE  ALT=\"+n+=+16+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The student bought 16 pens<BR>\n" );
document.write( "-------------------------<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+400%2Fn+-+9+=+400%2F%28+n%2B9+%29+ ALIGN=MIDDLE  ALT=\"+400%2Fn+-+9+=+400%2F%28+n%2B9+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+400%2F16+-+9+=+400%2F%28+16%2B9+%29+ ALIGN=MIDDLE  ALT=\"+400%2F16+-+9+=+400%2F%28+16%2B9+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+25+-+9+=+400%2F25+ ALIGN=MIDDLE  ALT=\"+25+-+9+=+400%2F25+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+16+=+16+ ALIGN=MIDDLE  ALT=\"+16+=+16+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );